Aqueous peroxide compositions and in particular the use of such compositions for laundering, bleaching, cleaning and/or disinfecting are well-known. For example, U.S. Pat. No. 4,642,198 discloses an aqueous liquid bleaching composition having a pH of from 1 to 6.5 comprised of 1 to 40 wt. % solid particulate substantially water-insoluble organic peroxy acid stably suspended in a surfactant structured liquid. European Patent Application 283 792 discloses storage-stable pourable aqueous bleach suspensions having a pH in the range of 1 to 6 and containing particulate water-insoluble peroxy carboxylic acid, xanthan gum or agars, hydratable neutral salt, optionally an acid for pH regulation, and aqueous liquid. European Patent Application 201 958 discloses pourable aqueous detergent and bleach compositions containing a linear alkyl benzene sulphonate, an ethoxylated fatty alcohol and an aliphatic peroxy dicarboxylic acid containing 8 to 13 carbon atoms wherein the pH of the composition is between 3.5 and 4.1. U.S. Pat. No. 3,996,152 describes a fabric bleaching composition having a viscosity in the range of 200 to 100,000 centipoise, the composition comprising a solid substantially water-insoluble peroxygen compound, a non-starch thickening agent, an acidifying agent to maintain the pH and a liquid carrier. U.S. Pat. No. 3,989,638 and 4,017,412 report fabric bleaching compositions comprised of certain substantially water-insoluble peroxygen compounds, a starch thickening agent and a liquid carrier.
Despite their usefulness in detergent, cleaning, disinfecting and bleaching formulations, a major difficulty remains in the use of aqueous suspensions of peroxy acids. As reported in European Patent Application 176 124 and in U.S. Pat. No. 4,790,949, dehydration of aqueous suspensions of peroxy acids produces a residue of solid peroxide particles. If such solid peroxide particles are not protected, desensitized or phlegmatised, there is a potential for ignitability and/or explosion if the residue is exposed to heat shock or abrasion. European Patent Application 176 124 reports that a pourable aqueous bleaching composition comprising a suspended peroxy carboxylic acid, 0.5 to 15 wt% of an alkali metal salt of an alkyl benzene sulphonic acid and 0.01 to 20 wt. % sodium sulphate, potassium sulphate or mixtures thereof is desensitized and therefore safe in that on drying the additives of the suspension coat the solid peroxide particles. U.S. Pat. No. 4,790,949 claims a storage resistant pourable-to-pasty aqueous bleaching agent suspension having a pH between 1 and 6 containing an aqueous carrier liquid, a particulate substantially water-insoluble peroxy carboxylic acid, an acidifying agent, 0.1 to 7% colloidal silicic acid and a hydrate-forming neutral salt which desensitizes carboxylic acids in an amount of 10-40% by weight of the peroxy carboxylic acid used. Sodium sulphate is the particularly preferred hydrate-forming neutral salt. U.S. Pat. No. 4,790,949 also discloses the use of additional desensitizing agents and in particular boric acid.
As mentioned above, European Patent Application No. 283 792 discloses a storage-stable, pourable aqueous bleach suspension comprising, inter alia, a particulate water-insoluble peroxy carboxylic acid and a hydrate-forming phlegmatising neutral salt such as Na.sub.2 SO.sub.4. In European Patent Application 240 481 stable liquid bleach compositions comprising certain water insoluble diperoxy acid particles, C.sub.11 -C.sub.13 linear alkyl benzene sulphonate surfactant, cumene sulphonate, magnesium sulphate, and sodium or potassium sulphate. The fact that magnesium sulphate, sodium sulphate and potassium sulphate are effective exotherm control agents is disclosed. U.S. Pat. No. 4,100,095 claims a dry granular bleach consisting essentially of boric acid and certain peroxy acid compounds. Boric acid is discussed in the specification as an exotherm control agent. "Exotherm control agents" have met ignition, heating (oven) and hot-wire tests. It has been surprisingly found that the addition of polyethylene glycol to suspensions of peroxy acids reduces the likelihood of combustion and/or explosion of such suspensions.
It should be particularly noted that GB 1 387 167 discloses a solid particulate bleaching agent comprised of a peroxy substance (such as a peroxy acid) which has been substantially surrounded by a water-impermeable material having a melting point between 30.degree. and 95.degree. C. and further surrounded by a water-soluble inorganic hydrate salt. Such double-coated particles may also be sprayed with polyethylene glycol. The specification of GB 1 387 167 suggests the polyethylene glycol spraying to make the salt coating more resistant to abrasion, to de-dust the particles and to control the rate of particle solution. GB 1 387 167 mentions desensitizing the peroxide only in the context of the water-impermeable material.
Further, a flame resistant peroxide composition consisting essentially of at least a minimum amount of water necessary to create flame resistance, certain saturated hydrocarbon ketone peroxides and sufficient water-soluble polyalkylene glycol to form a homogeneous condition between the peroxide and water is claimed in U.S. Pat. No. 3,507,800. According to the disclosure in U.S. Pat. No. 3,507,800, flame resistance is created by the presence of water and the polyethylene glycol is added as a mutual solvent for the peroxide and water.
It should also be noted that EP 167 375 discloses a stable peroxy acid bleaching composition comprising a surface active peroxy acid and at least one surfactant which forms a mixed micelle in aqueous solutions with said peroxy acid. Suitable surfactants are selected from anionic, nonionic, amphoteric and zwitterionic surfactants. Preferred are fatty acids or salts thereof. Among the numerous surfactants listed polyoxyethylenes are mentioned.
Japanese Patent Application 7114648 discloses the use of nonionic surfactant(s), polyoxyethylene glycol and/or polyoxypropylene glycol with tertbutylhydroperoxide in water to form a "homogeneous mixed liquid". Di-tert-butyl peroxide may also be present.
It is, however, a continuing problem to provide aqueous peroxide suspensions with an improved safety profile. For example, boric acid has a negative effect on the chemical stability of peroxide suspensions. Additionally, boric acid is undesirable since aqueous suspensions have an inherent maximum solid content and the presence of boric acid reduces the amount of solid peroxy acid which may be placed in the suspension.
Further, peroxy acids, and suspensions of such acids, are highly reactive and thus have a strong propensity for combustion and/or explosion. This raises transportation problems in that, for safety reasons, the amount of peroxy acid transported in a bulk container must be limited.